PID control of a zero stiffness magnetic suspension system

Abstract

–As a result of the developments in today's technology, magnetic suspensions have started to be used instead of traditional suspensions (mass-spring-damper) in order to prevent vibrations in structures. In conventional suspensions, there is an undesirable continuous force transfer from the ground to the user according to the action-reaction principle of the existing spring and damper used in the suspension system. Although the mass-spring-damper parameters are well adjusted in a conventional suspension, this transmitted force transfer cannot be reduced to zero. The main purpose of this study will be a magnetic suspension design to eliminate this undesirable situation. In the designed magnetic suspension, the magnet on the linear guide system will be tried to be kept in the zero transmitted force position with the help of only magnetic forces without any mechanical contact and lubrication. A total of 3 magnets will be used in the proposed magnetic suspension system. The magnet on the linear guide will be capable of free sliding and this sliding magnet will be actuated by the rotary magnets standing in a fixed position at ends of the linear guide system by using the repulsive or pulling forces. The position control of the sliding magnet is achieved by a PID control. Therefore, since no mechanical spring and damper connections will be used in the proposed suspension system, zero spring force effect could be created.